Consumer electronic systems commonly use infrared (IR) remote control to receive input from a user. In such systems, the user operates a remote control device, which transmits a modulated IR signal that carries data in accordance with a certain IR remote control protocol. The data may comprise commands for controlling the system and/or other information. The controlled system comprises an IR receiver, which extracts the data from the IR signal in order to carry out the desired commands.
Many different IR remote control protocols have been developed, and different manufacturers often use different protocols and different data rates for transmission. Common protocols include the RC-5 and RC-6 protocols (developed by Philips) and the NEC protocol (developed by Nippon Electric Corporation). These protocols are collectively referred to as Commercial Infrared (CIR) protocols.
Some systems and applications support more than a single IR protocol. For example, U.S. Pat. No. 5,917,631, whose disclosure is incorporated herein by reference, describes dual-protocol remote control methods and apparatus, which provide power-saving modes of operation and enable remote control of high data generating devices, such as a trackball. The patent describes a pulse position modulation protocol in which the position of a single pulse, such as an infrared pulse, is located in time in one of three or more locations. Dual-protocol remote control devices may be provided, wherein a first protocol is utilized in conjunction with a second protocol comprising the pulse position modulated system.
U.S. Patent Application Publication 2004/0153699, whose disclosure is incorporated herein by reference, describes a system and method for supporting two infrared signaling protocols in a single computing device. The computing device operates in a default signaling protocol, unless a priority signaling request is generated by an application program. Typically, the signaling protocols comprise an Infrared Data Association (IrDA) protocol and a CIR protocol, which are generally incompatible and may cause interference to one another. The disclosed methods ensure that the two protocols do not operate at the same time.